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South Korean (SK) navy corvette Cheonan sank on March 26, 2010 in the Yellow Sea near the sea border with North Korea. On May 20, 2010, after less than two months of investigation, the SK-appointed Joint Investigation Group (JIG) concluded that the Cheonan had been destroyed by a North Korean torpedo. The JIG presented as the conclusive evidence a set of the electron-dispersive spectroscopy (EDS) and x-ray diffraction data of the white powder samples extracted from the sunken ship, torpedo propulsion system and their own small-scale test-explosion experiment, and claimed that all of the three samples are aluminum oxide that should be produced at a high temperature environment (higher than at least 600oC) from an explosion. Here we report our scanning electron microscopy (SEM), EDS, and x-ray experiments on an Al powder that underwent melting and quenching. Contrary to the JIG claims, our data combined with our EDS simulations clearly show that the JIG’s identification of two of the white powders, from the sunken ship and torpedo fragments, is incorrect: those powders are not aluminum oxide that results from an explosion but they are aluminum sulfate hydroxide hydrate that can be produced naturally at a low temperature environment (lower than 100oC). Furthermore, the fact that the JIG’s EDS data of the third sample, from the test-explosion experiment, is identical to the EDS data of aluminum sulfate hydroxide hydrate is an anomaly. The test explosion would have produced aluminum oxide rather than aluminum sulfate hydroxide hydrate. The only scientifically possible explanation of the anomaly is that the EDS data of the test explosion was fabricated.
|Keywords:||Cheonan, Aluminum Oxide, Aluminum Sulfate, Hydroxide Hydrate, Torpedo Explosion, Korea|
Professor, Department of Physics, University of Virginia, Charlottesville, USA
Associate Professor, The Paul H. Nitze School of Advanced International Studies, Johns Hopkins University, Washington, USA